INDICATIONS AND USAGE Diphenhydramine hydrochloride injection, USP is effective in adults and pediatric patients, other than premature infants and neonates, for the following conditions when the oral form is impractical.

Antihistaminic For amelioration of allergic reactions to blood or plasma, in anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled and for other uncomplicated allergic conditions of the immediate type when oral therapy is impossible or contraindicated.

Motion Sickness For active treatment of motion sickness.

Antiparkinsonism For use in parkinsonism, when oral therapy is impossible or contraindicated, as follows: parkinsonism in the elderly who are unable to tolerate more potent agents, mild cases of parkinsonism in other age groups and in other cases of parkinsonism in combination with centrally acting anticholinergic agents.

WARNINGS Antihistamines should be used with considerable caution in patients with narrow-angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy or bladder-neck obstruction.

Local necrosis has been associated with the use of subcutaneous or intradermal use of intravenous diphenhydramine.

Use in Pediatric Patients In pediatric patients, especially, antihistamines in overdosage may cause hallucinations, convulsions or death.

As in adults, antihistamines may diminish mental alertness in pediatric patients.

In the young pediatric patient, particularly, they may produce excitation.

Use in the Elderly (approximately 60 years or older) Antihistamines are more likely to cause dizziness, sedation and hypotension in elderly patients.

ADVERSE REACTIONS The most frequent adverse reactions are italicized.

General Urticaria; drug rash; anaphylactic shock; photosensitivity; excessive perspiration; chills; dryness of mouth, nose and throat.

Cardiovascular System Hypotension, headache, palpitations, tachycardia, extrasystoles.

Hematologic System Hemolytic anemia, thrombocytopenia, agranulocytosis.

Nervous System Sedation , sleepiness , dizziness , disturbed coordination , fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paresthesia, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, neuritis, convulsions.

Gastrointestinal System Epigastric distress , anorexia, nausea, vomiting, diarrhea, constipation.

Genitourinary System Urinary frequency, difficult urination, urinary retention, early menses.

Respiratory System Thickening of bronchial secretions , tightness of chest and wheezing, nasal stuffiness.